In the combustion of a fuel, such as coal, oil, peat, waste, etc., in a combustion plant, such as a power plant, a hot process gas is generated, such process gas containing, among other components, dust particles, sometimes referred to as fly ash. The dust particles are often removed from the process gas by means of an electrostatic precipitator, also called ESP, for instance of the type illustrated in EP 2 078 563.
One problem associated with ESPs is the so-called back-corona effect, i.e. that a high electrical resistivity of a layer of already collected dust particles on a collecting electrode causes dielectric break-down of the dust layer during operation which may reduce the ESP collection efficiency.
EP 2 078 563 discloses an electrostatic precipitator with improved capability of reducing the negative effects of back-corona. The ESP is controlled based on an indicator signal which is indicative of the temperature of combustion air which is fed to the combustion air process.
Operating an ESP in accordance with EP 2 078 563 may reduce the negative effect of back-corona to some extent. However, back-corona effects may still influence the operation of the ESP in a negative manner.